This research seeks to clarify the nature of hypnosis and its therapeutic application as well as to facilitate our understanding of psychological factors in the treatment process. Hypnosis occurs in normal subjects and lends itself to systematic study, but it is also initimately related to a broad range of psychopathological conditions. The phenomenon is characterized by the subject's ability to experience distortions of perception or memory in response to appropriate suggestions. Though hypnosis occurs rapidly, it can result in changes analogous to those usually observed only in the context of significant, long-term dyadic relationships--providing a unique paradigm for their study. In an effort to objectify changes in subjective experience, a wide range of behavioral, phenomenological, psychological, and psychophysiological approaches will be utilized. The four major research thrusts focus on (a) the mechanisms involved in the induction of termination of hypnosis, (b) posthypnotic amnesia, both as a phenomenon in is own right and as a paradigm for normal and pathological memory processes, (c) the relationship between an individual's hypnotic responsivity on the one hand and his readiness for therapeutic change on the other. (This will be explored in the context of the suggestive treatment of smoking and obesity.). , (d) the relationship between hypnosis and other altered states of consciousness, using both physiological and psychological measures. This approach will include investigating the individual's ability to gain volitional control over apparently involuntary processes through biofeedback training, as well as relating this skill to the ability to enter hypnosis. Further, we hope to determine the extent to which (and the possible mechanisms by which) suggestions can influence vegetative functions. Not only will this program bear on the clinical use of hypnosis, but the special methodological procedures that need to be developed for the study of subjective events should be relevant to the understanding of all therapeutic change and help provide a bridge between behavioral, dynamic, and experimential approaches.